Services

LiDAR Control & QC

LiDAR analysis is a growing need in the GIS community and CompassData is at the cutting edge of this field.

Ground Truth

CompassData establishes and manages multi-use GNSS calibration sites for digital sensors and LiDAR, working with clients such as the National Oceanic and Atmospheric Administration (NOAA) and the United States Geological Survey (USGS).

Manual Editing/Post-processing

Besides providing the GNSS and Control necessary to ensure “Ground Truth” for LiDAR projects, CompassData’s team includes post-processing professionals who have the expertise to ensure Quality Control/Quality Assurance for LiDAR deliverables.

Postprocessing from CompassData includes GNSS and IMU data, in a LiDAR LAS file. This includes all relevant LiDAR attributes: classification, intensity, return information, GNSS timestamp, flight line information, etc.

Point Density: Number of LiDAR points per unit area (points per square meter)

Root Mean Square Error (RMSE): the Statistical value equal to the square root of the average of the squares of the differences between known points and modeled points in the LiDAR surface

Vertical Accuracy of LiDAR: is not an “absolute” accuracy. It is commonly specified as the Root Mean Square Error (RMSEz)

RMSEz is 68% confidence interval

RMSEz x 1.96 is the 95% confidence interval

RMSEz is the 99.7% confidence interval

Digital surface model of a light aggregate gravel quarry created using LiDAR data

What is LiDAR?

Airborne Light Detection and Ranging (LiDAR) – LiDAR is an active sensory system that uses laser light, an inertial measurement unit (IMU), and GNSS to rapidly measure distances between the sensor and points on the ground. This creates dense, highly accurate elevation data. Along with GNSS calibration sites within LiDAR collection grids that verify the GNSS, Ground Control is necessary to provide "Ground Truth" for LiDAR data analysis.

For more information on Field Surveys

Read this Case Study to find out more about recent Colorado Flood Mapping LiDAR projects that CompassData participated in.